Mechanisms of Thermal Ablation in CFRP With Absorption on Complex‐Shaped Reaction Surfaces During Picosecond Laser Irradiation

ABSTRACT The heterogeneity and three‐dimensional stacking structure of carbon fiber‐reinforced polymers (CFRP) lead to distinctive ablation morphologies. In this study, these characteristics are carefully considered to investigate the thermal ablation mechanisms of CFRP under picosecond laser irradiation. By analyzing the evolution process and the ablation characteristics in the experimental results, it is concluded that absorption is a key factor in determining the ablation outcome. A three‐dimensional transient finite element model is established. The level‐set method is used to control phase transitions, and the mass of vaporized products controls the removal rate. The heat source equation is improved to describe the interaction between light absorption and the reaction surface shape during processing. The simulation results indicate that the heterogeneity of CFRP and local variations in absorption jointly determine the ablation morphology. Quantitative comparison with experimental data demonstrates the model's predictive accuracy: for ablation depth, a key descriptor, the model achieves mean absolute error (MAE) of 15.06%, root‐mean‐square error (RMSE) of 21.30%, and R ² of 0.95, with stage‐wise trend agreement over time. The ablation morphology exhibits consistent features, such as dumbbell‐shaped fiber bundles and inclined fiber cross‐sections. The experiment further supports the reliability of the simulation results and theory.